{-# LANGUAGE NoImplicitPrelude #-}
{-# LANGUAGE OverloadedStrings #-}
{- |
   Module      : Text.Pandoc.Writers.Org
  Copyright    : © 2010-2015 Puneeth Chaganti <punchagan@gmail.com>
                   2010-2019 John MacFarlane <jgm@berkeley.edu>
                   2016-2019 Albert Krewinkel <tarleb+pandoc@moltkeplatz.de>
   License     : GNU GPL, version 2 or above

   Maintainer  : Albert Krewinkel <tarleb+pandoc@moltkeplatz.de>
   Stability   : alpha
   Portability : portable

Conversion of 'Pandoc' documents to Emacs Org-Mode.

Org-Mode:  <http://orgmode.org>
-}
module Text.Pandoc.Writers.Org (writeOrg) where
import Prelude
import Control.Monad.State.Strict
import Data.Char (isAlphaNum, toLower)
import Data.List (intersect, intersperse, isPrefixOf, partition, transpose)
import Data.Text (Text)
import Text.Pandoc.Class (PandocMonad, report)
import Text.Pandoc.Definition
import Text.Pandoc.Logging
import Text.Pandoc.Options
import Text.DocLayout
import Text.Pandoc.Shared
import Text.Pandoc.Templates (renderTemplate)
import Text.Pandoc.Writers.Shared

data WriterState =
  WriterState { stNotes   :: [[Block]]
              , stHasMath :: Bool
              , stOptions :: WriterOptions
              }

type Org = StateT WriterState

-- | Convert Pandoc to Org.
writeOrg :: PandocMonad m => WriterOptions -> Pandoc -> m Text
writeOrg opts document = do
  let st = WriterState { stNotes = [],
                         stHasMath = False,
                         stOptions = opts }
  evalStateT (pandocToOrg document) st

-- | Return Org representation of document.
pandocToOrg :: PandocMonad m => Pandoc -> Org m Text
pandocToOrg (Pandoc meta blocks) = do
  opts <- gets stOptions
  let colwidth = if writerWrapText opts == WrapAuto
                    then Just $ writerColumns opts
                    else Nothing
  metadata <- metaToContext opts
               blockListToOrg
               (fmap chomp . inlineListToOrg)
               meta
  body <- blockListToOrg blocks
  notes <- gets (reverse . stNotes) >>= notesToOrg
  hasMath <- gets stHasMath
  let main = body $+$ notes
  let context = defField "body" main
              . defField "math" hasMath
              $ metadata
  return $ render colwidth $
    case writerTemplate opts of
       Nothing  -> main
       Just tpl -> renderTemplate tpl context

-- | Return Org representation of notes.
notesToOrg :: PandocMonad m => [[Block]] -> Org m (Doc Text)
notesToOrg notes =
  vsep <$> zipWithM noteToOrg [1..] notes

-- | Return Org representation of a note.
noteToOrg :: PandocMonad m => Int -> [Block] -> Org m (Doc Text)
noteToOrg num note = do
  contents <- blockListToOrg note
  let marker = "[fn:" ++ show num ++ "] "
  return $ hang (length marker) (text marker) contents

-- | Escape special characters for Org.
escapeString :: String -> String
escapeString = escapeStringUsing $
               [ ('\x2014',"---")
               , ('\x2013',"--")
               , ('\x2019',"'")
               , ('\x2026',"...")
               ]

isRawFormat :: Format -> Bool
isRawFormat f =
  f == Format "latex" || f == Format "tex" || f == Format "org"

-- | Convert Pandoc block element to Org.
blockToOrg :: PandocMonad m
           => Block         -- ^ Block element
           -> Org m (Doc Text)
blockToOrg Null = return empty
blockToOrg (Div (_,classes@(cls:_),kvs) bs) | "drawer" `elem` classes = do
  contents <- blockListToOrg bs
  let drawerNameTag = ":" <> text cls <> ":"
  let keys = vcat $ map (\(k,v) ->
                       ":" <> text k <> ":"
                       <> space <> text v) kvs
  let drawerEndTag = text ":END:"
  return $ drawerNameTag $$ cr $$ keys $$
           blankline $$ contents $$
           blankline $$ drawerEndTag $$
           blankline
blockToOrg (Div (ident, classes, kv) bs) = do
  contents <- blockListToOrg bs
  -- if one class looks like the name of a greater block then output as such:
  -- The ID, if present, is added via the #+NAME keyword; other classes and
  -- key-value pairs are kept as #+ATTR_HTML attributes.
  let isGreaterBlockClass = (`elem` ["center", "quote"]) . map toLower
      (blockTypeCand, classes') = partition isGreaterBlockClass classes
  return $ case blockTypeCand of
    (blockType:classes'') ->
      blankline $$ attrHtml (ident, classes'' <> classes', kv) $$
      "#+BEGIN_" <> text blockType $$ contents $$
      "#+END_" <> text blockType $$ blankline
    _                     ->
      -- fallback with id: add id as an anchor if present, discard classes and
      -- key-value pairs, unwrap the content.
      let contents' = if not (null ident)
                      then "<<" <> text ident <> ">>" $$ contents
                      else contents
      in blankline $$ contents' $$ blankline
blockToOrg (Plain inlines) = inlineListToOrg inlines
-- title beginning with fig: indicates that the image is a figure
blockToOrg (Para [Image attr txt (src,'f':'i':'g':':':tit)]) = do
  capt <- if null txt
             then return empty
             else ("#+CAPTION: " <>) `fmap` inlineListToOrg txt
  img <- inlineToOrg (Image attr txt (src,tit))
  return $ capt $$ img $$ blankline
blockToOrg (Para inlines) = do
  contents <- inlineListToOrg inlines
  return $ contents <> blankline
blockToOrg (LineBlock lns) = do
  let splitStanza [] = []
      splitStanza xs = case break (== mempty) xs of
        (l, [])  -> [l]
        (l, _:r) -> l : splitStanza r
  let joinWithLinefeeds  = nowrap . mconcat . intersperse cr
  let joinWithBlankLines = mconcat . intersperse blankline
  let prettifyStanza ls  = joinWithLinefeeds <$> mapM inlineListToOrg ls
  contents <- joinWithBlankLines <$> mapM prettifyStanza (splitStanza lns)
  return $ blankline $$ "#+BEGIN_VERSE" $$
           nest 2 contents $$ "#+END_VERSE" <> blankline
blockToOrg (RawBlock "html" str) =
  return $ blankline $$ "#+BEGIN_HTML" $$
           nest 2 (text str) $$ "#+END_HTML" $$ blankline
blockToOrg b@(RawBlock f str)
  | isRawFormat f = return $ text str
  | otherwise     = do
      report $ BlockNotRendered b
      return empty
blockToOrg HorizontalRule = return $ blankline $$ "--------------" $$ blankline
blockToOrg (Header level attr inlines) = do
  contents <- inlineListToOrg inlines
  let headerStr = text $ if level > 999 then " " else replicate level '*'
  let drawerStr = if attr == nullAttr
                  then empty
                  else cr <> nest (level + 1) (propertiesDrawer attr)
  return $ headerStr <> " " <> contents <> drawerStr <> blankline
blockToOrg (CodeBlock (_,classes,kvs) str) = do
  let startnum = maybe "" (\x -> ' ' : trimr x) $ lookup "startFrom" kvs
  let numberlines = if "numberLines" `elem` classes
                      then if "continuedSourceBlock" `elem` classes
                             then " +n" ++ startnum
                             else " -n" ++ startnum
                      else ""
  let at = map pandocLangToOrg classes `intersect` orgLangIdentifiers
  let (beg, end) = case at of
                      []    -> ("#+BEGIN_EXAMPLE" ++ numberlines, "#+END_EXAMPLE")
                      (x:_) -> ("#+BEGIN_SRC " ++ x ++ numberlines, "#+END_SRC")
  return $ text beg $$ nest 2 (text str) $$ text end $$ blankline
blockToOrg (BlockQuote blocks) = do
  contents <- blockListToOrg blocks
  return $ blankline $$ "#+BEGIN_QUOTE" $$
           nest 2 contents $$ "#+END_QUOTE" $$ blankline
blockToOrg (Table caption' _ _ headers rows) =  do
  caption'' <- inlineListToOrg caption'
  let caption = if null caption'
                   then empty
                   else "#+CAPTION: " <> caption''
  headers' <- mapM blockListToOrg headers
  rawRows <- mapM (mapM blockListToOrg) rows
  let numChars = maximum . map offset
  -- FIXME: width is not being used.
  let widthsInChars =
       map ((+2) . numChars) $ transpose (headers' : rawRows)
  -- FIXME: Org doesn't allow blocks with height more than 1.
  let hpipeBlocks blocks = hcat [beg, middle, end]
        where sep'   = vfill " | "
              beg    = vfill "| "
              end    = vfill " |"
              middle = hcat $ intersperse sep' blocks
  let makeRow = hpipeBlocks . zipWith lblock widthsInChars
  let head' = makeRow headers'
  rows' <- mapM (\row -> do cols <- mapM blockListToOrg row
                            return $ makeRow cols) rows
  let border ch = char '|' <> char ch <>
                  (hcat . intersperse (char ch <> char '+' <> char ch) $
                          map (\l -> text $ replicate l ch) widthsInChars) <>
                  char ch <> char '|'
  let body = vcat rows'
  let head'' = if all null headers
                  then empty
                  else head' $$ border '-'
  return $ head'' $$ body $$ caption $$ blankline
blockToOrg (BulletList items) = do
  contents <- mapM bulletListItemToOrg items
  -- ensure that sublists have preceding blank line
  return $ blankline $$
           (if isTightList items then vcat else vsep) contents $$
           blankline
blockToOrg (OrderedList (start, _, delim) items) = do
  let delim' = case delim of
                    TwoParens -> OneParen
                    x         -> x
  let markers = take (length items) $ orderedListMarkers
                                      (start, Decimal, delim')
  let maxMarkerLength = maximum $ map length markers
  let markers' = map (\m -> let s = maxMarkerLength - length m
                            in  m ++ replicate s ' ') markers
  contents <- zipWithM orderedListItemToOrg markers' items
  -- ensure that sublists have preceding blank line
  return $ blankline $$
           (if isTightList items then vcat else vsep) contents $$
           blankline
blockToOrg (DefinitionList items) = do
  contents <- mapM definitionListItemToOrg items
  return $ vcat contents $$ blankline

-- | Convert bullet list item (list of blocks) to Org.
bulletListItemToOrg :: PandocMonad m => [Block] -> Org m (Doc Text)
bulletListItemToOrg items = do
  contents <- blockListToOrg items
  return $ hang 2 "- " contents $$
          if endsWithPlain items
             then cr
             else blankline


-- | Convert ordered list item (a list of blocks) to Org.
orderedListItemToOrg :: PandocMonad m
                     => String   -- ^ marker for list item
                     -> [Block]  -- ^ list item (list of blocks)
                     -> Org m (Doc Text)
orderedListItemToOrg marker items = do
  contents <- blockListToOrg items
  return $ hang (length marker + 1) (text marker <> space) contents $$
          if endsWithPlain items
             then cr
             else blankline

-- | Convert definition list item (label, list of blocks) to Org.
definitionListItemToOrg :: PandocMonad m
                        => ([Inline], [[Block]]) -> Org m (Doc Text)
definitionListItemToOrg (label, defs) = do
  label' <- inlineListToOrg label
  contents <- vcat <$> mapM blockListToOrg defs
  return $ hang 2 "- " (label' <> " :: " <> contents) $$
      if isTightList defs
         then cr
         else blankline

-- | Convert list of key/value pairs to Org :PROPERTIES: drawer.
propertiesDrawer :: Attr -> Doc Text
propertiesDrawer (ident, classes, kv) =
  let
    drawerStart = text ":PROPERTIES:"
    drawerEnd   = text ":END:"
    kv'  = if classes == mempty then kv  else ("CLASS", unwords classes):kv
    kv'' = if ident == mempty   then kv' else ("CUSTOM_ID", ident):kv'
    properties = vcat $ map kvToOrgProperty kv''
  in
    drawerStart <> cr <> properties <> cr <> drawerEnd
 where
   kvToOrgProperty :: (String, String) -> Doc Text
   kvToOrgProperty (key, value) =
     text ":" <> text key <> text ": " <> text value <> cr

attrHtml :: Attr -> Doc Text
attrHtml (""   , []     , []) = mempty
attrHtml (ident, classes, kvs) =
  let
    name = if null ident then mempty else "#+NAME: " <> text ident <> cr
    keyword = "#+ATTR_HTML"
    classKv = ("class", unwords classes)
    kvStrings = map (\(k,v) -> ":" <> k <> " " <> v) (classKv:kvs)
  in name <> keyword <> ": " <> text (unwords kvStrings) <> cr

-- | Convert list of Pandoc block elements to Org.
blockListToOrg :: PandocMonad m
               => [Block]       -- ^ List of block elements
               -> Org m (Doc Text)
blockListToOrg blocks = vcat <$> mapM blockToOrg blocks

-- | Convert list of Pandoc inline elements to Org.
inlineListToOrg :: PandocMonad m
                => [Inline]
                -> Org m (Doc Text)
inlineListToOrg lst = hcat <$> mapM inlineToOrg (fixMarkers lst)
  where fixMarkers [] = []  -- prevent note refs and list markers from wrapping, see #4171
        fixMarkers (Space : x : rest) | shouldFix x =
          Str " " : x : fixMarkers rest
        fixMarkers (SoftBreak : x : rest) | shouldFix x =
          Str " " : x : fixMarkers rest
        fixMarkers (x : rest) = x : fixMarkers rest

        shouldFix Note{} = True -- Prevent footnotes
        shouldFix (Str "-") = True -- Prevent bullet list items
        -- TODO: prevent ordered list items
        shouldFix _ = False

-- | Convert Pandoc inline element to Org.
inlineToOrg :: PandocMonad m => Inline -> Org m (Doc Text)
inlineToOrg (Span (uid, [], []) []) =
  return $ "<<" <> text uid <> ">>"
inlineToOrg (Span _ lst) =
  inlineListToOrg lst
inlineToOrg (Emph lst) = do
  contents <- inlineListToOrg lst
  return $ "/" <> contents <> "/"
inlineToOrg (Strong lst) = do
  contents <- inlineListToOrg lst
  return $ "*" <> contents <> "*"
inlineToOrg (Strikeout lst) = do
  contents <- inlineListToOrg lst
  return $ "+" <> contents <> "+"
inlineToOrg (Superscript lst) = do
  contents <- inlineListToOrg lst
  return $ "^{" <> contents <> "}"
inlineToOrg (Subscript lst) = do
  contents <- inlineListToOrg lst
  return $ "_{" <> contents <> "}"
inlineToOrg (SmallCaps lst) = inlineListToOrg lst
inlineToOrg (Quoted SingleQuote lst) = do
  contents <- inlineListToOrg lst
  return $ "'" <> contents <> "'"
inlineToOrg (Quoted DoubleQuote lst) = do
  contents <- inlineListToOrg lst
  return $ "\"" <> contents <> "\""
inlineToOrg (Cite _  lst) = inlineListToOrg lst
inlineToOrg (Code _ str) = return $ "=" <> text str <> "="
inlineToOrg (Str str) = return . text $ escapeString str
inlineToOrg (Math t str) = do
  modify $ \st -> st{ stHasMath = True }
  return $ if t == InlineMath
              then "$" <> text str <> "$"
              else "$$" <> text str <> "$$"
inlineToOrg il@(RawInline f str)
  | isRawFormat f = return $ text str
  | otherwise     = do
      report $ InlineNotRendered il
      return empty
inlineToOrg LineBreak = return (text "\\\\" <> cr)
inlineToOrg Space = return space
inlineToOrg SoftBreak = do
  wrapText <- gets (writerWrapText . stOptions)
  case wrapText of
       WrapPreserve -> return cr
       WrapAuto     -> return space
       WrapNone     -> return space
inlineToOrg (Link _ txt (src, _)) =
  case txt of
        [Str x] | escapeURI x == src ->  -- autolink
             return $ "[[" <> text (orgPath x) <> "]]"
        _ -> do contents <- inlineListToOrg txt
                return $ "[[" <> text (orgPath src) <> "][" <> contents <> "]]"
inlineToOrg (Image _ _ (source, _)) =
  return $ "[[" <> text (orgPath source) <> "]]"
inlineToOrg (Note contents) = do
  -- add to notes in state
  notes <- gets stNotes
  modify $ \st -> st { stNotes = contents:notes }
  let ref = show $ length notes + 1
  return $ "[fn:" <> text ref <> "]"

orgPath :: String -> String
orgPath src =
  case src of
    []      -> mempty         -- wiki link
    ('#':_) -> src            -- internal link
    _       | isUrl src      -> src
    _       | isFilePath src -> src
    _       -> "file:" <> src
 where
   isFilePath :: String -> Bool
   isFilePath cs = any (`isPrefixOf` cs) ["/", "./", "../", "file:"]

   isUrl :: String -> Bool
   isUrl cs =
     let (scheme, path) = break (== ':') cs
     in all (\c -> isAlphaNum c || c `elem` (".-"::String)) scheme
          && not (null path)

-- | Translate from pandoc's programming language identifiers to those used by
-- org-mode.
pandocLangToOrg :: String -> String
pandocLangToOrg cs =
  case cs of
    "c"          -> "C"
    "cpp"        -> "C++"
    "commonlisp" -> "lisp"
    "r"          -> "R"
    "bash"       -> "sh"
    _            -> cs

-- | List of language identifiers recognized by org-mode.
orgLangIdentifiers :: [String]
orgLangIdentifiers =
  [ "asymptote", "awk", "C", "C++", "clojure", "css", "d", "ditaa", "dot"
  , "calc", "emacs-lisp", "fortran", "gnuplot", "haskell", "java", "js"
  , "latex", "ledger", "lisp", "lilypond", "matlab", "mscgen", "ocaml"
  , "octave", "org", "oz", "perl", "plantuml", "processing", "python", "R"
  , "ruby", "sass", "scheme", "screen", "sed", "sh", "sql", "sqlite"
  ]
